Earticle

본 연구는 3D 프린터로 제작 도구를 이용하여 근육의 주행방향에 대해 강찰법 방향의 차이로 인한 근활성 도 차이를 확인하고자 한다. 대상자는 건강한 20대 성인 20명으로 진행하였고, IASTM을 근육 주행방향의 수직 강찰법 중재(수직군)와 근육 주행방향의 수평 강찰법 중재(수평군)를 적용하였으며 대상자를 각 10명씩 배치하였 다. 모든 대상자는 중재 전과 후의 근활성도를 독립표본 t-검정과 대응표본 t-검정을 사용하여 측정, 비교하였다. 본 연구의 결과는 수평군에서 근활성도가 감소하였으나 수직군에서 근활성도는 유의한 증가가 나타났다. 이는 IASTM의 적용에 방향성의 차이가 의미가 있음을 알 수 있다.

This study aim to verify the difference in muscle activity due to difference in the direction of the stroking method for the stroke direction of the muscles using a tool made by a 3D printer. The subjects were conducted with 20 healthy adults in their 20s, and IASTM applied the intervention of the perpendicular stroking on the direction of muscle driving and intervention of the pararell stroking on the direction of muscle driving, with 10 each deployed. All subjects measured the muscle activity before intervention, and the muscle activity was measured and compared with the independent T test and the paired T test. The results of this study showed a significant increase in muscle activity in vertical groups, although the muscle activity in horizontal groups decreased. It was that differences in direction are significant in the application of IASTM.

지형적 경계 (geofence)란 무인기가 침범하거나 또는 벗어나지 말아야 할 영역을 설정해 놓은 가상의 경계로서, 저고도 무인기 교통관리체계(UAS traffic management)의 필수적인 구성요소 중 하나이다. 본 연구에서는 perpendicular 알고리즘을 개선하여 지형적 경계를 단순화하는 기법을 제안한다. 제안된 기법을 실제 건물을 측정하여 얻은 데이터에 적용하여 성능을 평가하였으며, 제안된 방법이 기존 방법에 비해 공간적 낭비를 최소화하면서도 꼭짓점의 개수를 효과적으로 줄임을 확인하였다.

Geofence defines the area that UAS should not enter or exit to ensure the safety of their operations, and is considered as one of critical capabilities of the UTM (UAS traffic management) system. In this study, a geofence simplification method using modified perpendicular algorithm is proposed. The performances of the proposed geofence simplification method were evaluated with actual building data, and the evaluation results confirmed that the number of vertices can be effectively reduced while minimizing the spatial size of the geofence.

The Lorentz force distribution of a high T c superconducting tape with increasing transport currents in magnetic field (Ha) was visualized. The external magnetic field was applied normally to the coated conductor tape surface after zero-field cooling, and the transport current (Ia) was increased stepwise from 0 to 90 % of the values of the critical current (Ic (Ha}) at applied filed, Ha. The field distribution (H(x}) near the sample surface across the tape width (2w) was measured using the scanning Hall probe method. Applying an inversion to the measured field distribution, we obtained the underlying current distribution (J(x}), from which the magnetic induction, B(x) was calculated with Biot-Savart law. Then Lorentz force per unit length was calculated using F(x}=J(x}xB(x}, which appears to be very inhomogeneous along the tape width due to the complicated distributions of J(x} and B(x}.

불연속 지형을 지나는 천수 흐름을 해석할 수 있는 Hwang의 기법이 채택된 수치 모의를 댐 붕괴 흐름에 의한 직립 홍수터의 범람 실험과 비교하였다. 모의 결과는 저수지, 저수로, 홍수터로 이루어진 실험 수로에서 측정한 결과와 잘 일치하였다. 특히, 댐 붕괴 흐름이 직립 홍수터로 차고 빠지는 과정이 잘 모의되었다. 흐름 저항의 종류에 따른 모의 결과의 차이는 미미하였다. 이 연구를 바탕으로 도심 하천의 범람 예측에서 정확도를 높일 수 있을 것으로 기대된다.

Numerical simulation with Hwang's scheme, which can analyze shallow-water flow over discontinuous topography, was compared with a laboratory experiment of flooding on a perpendicular floodplain with dam-break flows. The simulation results were in good agreement with the results measured in an experimental flume with a reservoir, channel, and floodplain. The wetting and drying process on a perpendicular floodplain with a dam-break flow was particularly well simulated. The difference in simulation results according to the type of flow resistance was insignificant. The results of this study are expected to improve the accuracy of predicting inundation in urban rivers.

Recently, it is proposed to make striations on the YBCO coated conductor and to transpose each other as one of the solutions to decrease the perpendicular magnetization loss. For large power application using HTS, the stacked conductor packing the YBCO coated conductors should be used because single conductor is limited in flowing of demanded large current. In this paper, we research the affect of the striation and continuously transposed stacking geometry on the magnetization loss in perpendicularly exposed magnetic field. Several short samples having different number of striation and continuously transposed stack are prepared and tested in perpendicularly exposed magnetic field for the magnetization loss characteristics. The magnetization loss of striated sample was lower than sample without striation. The reduction effect on magnetization loss by the striation is obviously appeared in higher field and lower number of stack and decreased as increasing the transposed stacking number. Also, the reduction effect by transposed stack is obviously appeared in lower field at lower number of striation and isn’t appeared at higher striation number and higher magnetic field.

In this paper we analyze various mathematical theorems and problems related with a perpendicular of triangle, classify the these as followings: perpendicular's properties related with its length, triangle's area, and triangle's angle. We suggest proof process of these properties in detail, and discuss didactical meaning of the proof and property.

이 논문에서는 초등수학에서 평행의 정의에 등장하는 ‘한 직선에 수직인 두 직 선’이라는 문구에 주목하고 그것이 어떤 쓰임이 있는지 알아보았다. 이를 위해 우 리나라 중학교 교과서와 초등학교 교과서를 대비하여 초등의 특징을 찾고, 일본과 싱가포르의 초등학교 수학 교과서에서는 그 특징이 나타나는 양상을 살펴보았다. 이어 제1차부터 현재까지 초등수학 교과서에서 평행과 평행선이 어떻게 정의되어 왔는지를 살펴보고 각 교과서에서 ‘한 직선에 수직인 두 직선’이 어떤 쓰임을 가졌는지를 조사하였다. ‘한 직선에 수직인 두 직선’은, 평행선 여부 판정하기, 평행선 긋기, 평행선 사이의 거리 구하기, 사각형에서 평행 여부 판단하기, 평행사 변형 그리기 등 모두 다섯 가지 쓰임이 있다. 5차와 6차에는 이 다섯 가지 쓰임이 모두 교과서에 드러나 있는 반면에 2015 개정 교육과정에서는 상당히 축소된 것으 로 나타났다. 교사나 교과서 저자들이‘한 직선에 수직인 두 직선’이라는 아이디 어가 평행 지도에서 어떤 의미가 있는지를 인식하고 더 나아가 교과용 도서에 이 를 어떻게 반영할 것인지 판단할 때 이 논문이 기초 자료가 될 수 있을 것이다.

In this paper, we wanted to find out why the idea of 'two straight lines perpendicular to one line' is contained in the parallel definition of elementary school mathematics. To this end, we examined how parallel and parallel lines have been defined in the primary math textbooks presented from the first to the present, and what use 'two straight lines perpendicular to one line' in each textbook was. The "two straight lines perpendicular to one straight line" had five uses. While all five were shown in textbooks in the fifth and sixth rounds, the 2015 revised curriculum showed a sharp reduction. In elementary mathematics, the mathematics education community needs to recognize what the idea of "two straight lines perpendicular to one line" means in parallel lines and reflect them in textbooks.

본 논문은 고성능 다결정 실리콘(Poly-Si) 박막 트랜지스터 (Thin Film Transistor)에서 단일 수직 그레인 경계(Single Perpendlcular Grain Boundary)가 고온 캐리어 스트레스(Hot Carrier Stress) 및 정전류 안정성 평가에서 어떠한 효과를 보이는가에 대해서 살펴보았다. 고온 캐리어 스트레스 하에서($V_G=V_{TH}+1V,\;V_D$ =12V),그레이 경계가 없는 다결정 실리콘 TFT와 비교했을 때 그레인 경계를 가지고 있는 다결정 실리를 TFT는 전기 전도(Electric Conduction)에 작용하는 자유 캐리어(Free Carrier)의 개수가 적기 때문에 상대적으로 더욱 우수한 전기적 특성을 나타낸다. 먼저 1000초 동안 고온 캐리어 스트레스를 가해준 결과 단일 그레인 경계를 가진 다결정 실리콘에서의 트랜스 컨덕턴스(Transconductance)의 이동 정도는 5% 미만으로 확인되었다. 반면에 같은 스트레스 조건 하에서 그레인 경계가 존재하지 않는 다결정 실리콘의 경우에는 그 이동 정도가 약 25%에 달하는 것으로 측정되었다. 다음으로 정전류 스트레스(Constant Current Stress) 인가시, 수직형 그레인 경계가 채널 영역 내에 존재하지 않는 다결정 실리콘 TFT는 드레인 접합 부분의 전계 세기를 비교했을 때, 그레인 경계를 가지고 있는 다결정 실리콘 TFT보다 상대적으로 낮은 원 인 때문에 적게 열화되는(Degraded) 특성을 확인할 수 있었다.

This study examined the structure and perpendicular magnetization of FePt films grown on Pt/Fe/MgO(100) buffered Si(100) substrates by molecular beam epitaxy. The [Fe(0.17nm)/Pt(0.2nm)]$_N$ multilayers were prepared at room temperature to form a $L1_0$-FePt phase after vacuum annealing. Perpendicular magnetic anisotropy (PMA) was observed in the films after at least 15 repetitions (N = 15) of Fe/Pt deposition and annealing at $300{^{\circ}C}$ for 1 hour. Careful structural analysis of the films was carried out by x-ray diffraction and high-resolution transmission electron microscopy. These results will assist in the development of the low temperature $L1_0$- FePt deposition process, which will be essential for future extremely high density magnetic recording media.

Perpendicular magnetization curves and crystal textures of $[Pd(0.8 nm)/Co(0.8 nm)]_5/FeMn$ multilayers having an exchange-biased perpendicular magnetic anisotropy as a function of FeMn thickness and annealing temperature were measured. As FeMn thickness increases from 0 to 21 nm, the perpendicular exchange biasing field ($H_{ex}$) obtained the maximum value of 130 Oe at FeMn thickness 12 nm. As the annealing temperature increases to $240^{\circ}C$, the H_ex increased from 115 Oe to 190 Oe and the exchange-biased perpendicular magnetic anisotropy disappeared at $330^{\circ}C$.

First-principles calcualtions of the magnetocrystalline anisotropy energy have been performed and it is predicted that the perpendicular magnetic anisotropy energy of a Au(Fe-Co)(111) multilayer will be larger than that of a Au/Co multilayer. Then we have actually synthesized the Au/(Fe-Co) multilayers by MBE method and found that theses multilayers show the predicted properites. The surface magnetic anisotropy energy is $0.64mj/m^2$, which is larger than the value reported previously for the Au/Co multilayer by 10%. Ther result indicated the possibility to control the magnetic anisortopy by changing the number of valence electrons.